OK I thought you wanted the graph to go from left to right. Yeah, I have seen that glitch a few times (but rare). I think you can ignore it for now, we can look into it once we get time. It is not a priority.
I've tried one more approach here. If our data array is full, this graph shifting won't happen. So, if we initialize our data list with null values, there won't be any visible shift. What do you think about this solution?